It has been a long standing problem in the cylinder handling industry to efficiently take a cylindrical object from a random group of cylindrical objects of various sizes and orientations, align the single object in a predetermined direction and direct it to a cylinder handling apparatus. This problem arises in the log handling industry. Numerous machines and processes have been designed over the years in an effort to develop an apparatus and a method of efficiently handling a wide range of logs of varying diameters and lengths mixed butts and ends and aligning them one at a time in a common direction and feeding them without interruption to a log processing machine such as a debarker or a chip and saw apparatus.
The applicant is aware of the following patents which disclose various devices for processing logs.
______________________________________ Issue Date Inventor ______________________________________ Canadian Patent No. 789,368 July 9, 1968 Ahlstedt 920,544 February 6, 1973 Lindblom 922,659 March 13, 1973 Rysti 980,820 December 30, 1975 Hartzell and Gunnerman 989,427 May 18, 1976 Valo 1,048,562 February 13, 1979 Danielsson and Ekhoim 1,114,408 December 15, 1981 Valo U.S. Pat. No. 2,751,781 June 26, 1956 McConnell 3,584,726 June 15, 1971 Hartzell ______________________________________
Ideally, a log handling apparatus capable of handling a group of logs of various diameters, lengths and orientations, and single feeding them in an aligned manner to a log processing apparatus should be able to run without interruption and be capable of feeding the logs to the log processing apparatus virtually end to end with one another. In this way, a maximum number of logs are processed in a given time. However, in practice, apparatus designed for this purpose are prone to breakdown, complexity, or do not carry out the job of separating the logs individually and feeding them one at a time without frequent interruptions. Thus, it is not uncommon for the apparatus to fail to make a separation between individual logs and thus, the operator must stop the machine, separate the plurality of logs and ensure that they are fed one at a time to the log processing apparatus. Interruptions of this sort are costly and labour intensive.
Of the devices disclosed and claimed in the references listed, two devices in particular are purported to successfully select a log from a group of logs and feed it to a log processing apparatus. The Ahlstedt patent, Canadian Pat. No. 789,368, discloses an apparatus for the selection and sidewise delivery of selected sets of long rollable objects of varying diameters from a closely spaced group of such objects, such as logs. In the device, a lift arm holds the logs back in the "up" position, and releases one log while in the "down" position. At the same time, a second log is allowed to lodge in a pocket to hold back remaining logs. The Ahlstedt apparatus appears to deal adequately with logs of relatively uniform diameter but it appears to be weak in dealing with logs of small diameter mixed with logs of large diameter. Lodging of a small log in the retaining pocket would increase the likelihood that a following larger diameter log would be pushed over the smaller log and hence disrupt operation.
Canadian Pat. No. 1,114,408, Valo, discloses and claims an apparatus which is designed specifically for the purpose of handling logs of varying diameter and feeding them one at a time to a log processing apparatus. However, the apparatus disclosed is relatively complex, expensive, and in practice has been found to be prone to breakdown due to its complexity. The apparatus utilizes a dual disc arrangement for separating the logs. The two discs rotate on separate shafts in opposite direction and are provided with peripheral notches which, in the extreme positions of the rotary movement of the discs, are directed substantially toward the inlet end and the outlet side. In practice, it has been found that the Valo apparatus cannot be operated efficiently at high speed without frequent breakdown.